Module Rdf_dt

module Rdf_dt: sig .. end

Computing values in Sparql, mapping to/from RDF terms.

A value can be an error, and propagated in computations.

type error =

`\|`	`Type_error of value * string`	`(*`	The value has not the given expected "type"	`*)`
`\|`	`Invalid_literal of Rdf_node.literal`	`(*`	Invalid literal: bad integer string for an integer, ...	`*)`
`\|`	`Exception of exn`	`(*`	To keep the original exception which resulted in an error.	`*)`

type value =

`\|`	`Err of error`	`(*`	Value is an error	`*)`
`\|`	`Blank of string`	`(*`	A blank node with its label	`*)`
`\|`	`Iri of Rdf_uri.uri`	`(*`	An URI.	`*)`
`\|`	`String of string`	`(*`	A string literal.	`*)`
`\|`	`Int of int`	`(*`	An integer.	`*)`
`\|`	`Float of float`	`(*`	A decimal, float or double.	`*)`
`\|`	`Bool of bool`	`(*`	A Boolean.	`*)`
`\|`	`Datetime of Netdate.t`	`(*`	A datetime.	`*)`
`\|`	`Ltrl of string * string option`	`(*`	A literal string with an optional language tag.	`*)`
`\|`	`Ltrdt of string * Rdf_uri.uri`	`(*`	A literal value with a specified datatype.	`*)`

exception Error of error

val error : error -> 'a

Raise a Rdf_dt.Error exception with the given error.

val date_fmt : string

Default date format.

val string_of_value : value -> string

Return a string to show the given value.

module ValueOrdered: sig .. end

module VMap: Map.S  with type key = value

Maps over values.

module VSet: Set.S  with type elt = value

Sets of values.

val string_of_error : error -> string

Return a human-readable message from the given error.

val iri : Rdf_uri.uri -> value -> value

iri base v returns a Iri value, ensure the given value is an URI. If it is a literal string, convert it to an URI, eventually appending to the base uri if the string expresses a relative URI.

val datatype : value -> value

datatype v returns the URI of the datatype of the value. If v is Err, Blank or Iri, return Err.

val string_literal : value -> string * string option

string_literal v returns a pair (string, optional language tag) if v is String of Ltrl. Else return Err.

val string : value -> value

string v returns a String value, converting any value to a string, except Err and Blank for which Err is returned.

val int : value -> value

int v returns a Int value, trying to convert literal values to an integer. Return Err if v is Err, Blank or Iri, or if the literal value could not be converted to an integer. Floats are truncated.

val float : value -> value

Same as Rdf_dt.int but for floats.

val bool : value -> value

Same as Rdf_dt.int but for booleans. Bool true, String "true", String "1", Int n with n<>0 and Float f when f is not nan nor zero evaluate to Bool true. Bool false, String "false", String "0", Int 0 and Float f when f is nan or zero evaluate to Bool false. Any other value evaluates to Err.

val datetime : value -> value

datetime v returns a Datetime, if possible. String literals are converted if possible; else Err is returned.

val ltrl : value -> value

Same as Rdf_dt.string, but languge tag is kept is present (i.e. if the value is a Ltrl).

val numeric : value -> value

Try to convert the given value to an Int or else to a Float, if the value is not already Int or Float.

val of_literal : Rdf_node.literal -> value

of_literal lit returns a value from a literal node.

val of_node : Rdf_node.node -> value

of_node node returns a value from an RDF node.

val to_node : value -> Rdf_node.node

to_node v converts the given value to an RDF node. If v is Error e, then exception e is raised.